Question

我想这样做:

/* example filename: config_load.php */

$config_file = "c:path	ofile.php";

function read_config($file = &$config_file)
{
$settings = array();
$doc = new DOMDocument( 1.0 );
$doc->load($file); 
$xpath = new DOMXPath($doc); 
$all=$xpath->query( appSettings/add );
foreach ($all as $setting) {$settings[$setting->getAttribute( key )]=$setting->getAttribute( value );}

return $settings;
}

/* end config_load.php */

所以当我打电话给文件的时候, 它就像这样...

require_once "config_load.php";
// $config_file = "c:path	ofile2.php"; //could also do this
$config = read_config();

这样, 如果我不指定文件, 它就会读取默认配置文件。在调用函数之前, 我也可以在任何地方定义 $config_ file 。无法调用配置_ load 文件的人不需要担心是否能够加载其它文件, 他们可以在调用读取_ config () 之前在任何地方定义它。

Answer 1

这是不可能的:

默认值必须是不变表达式,而不是变量、类别成员或函数调用。

~http://www.php.net/manual/en/offices.arguments.php#formes.arguments.php#formations.arguments.default" rel=“nofollows”>http://www.php.net/manual/en/wices.arguments.php#forms.arguments.fault

然而,你可以像这样绕过它:

function read_config($file = false) {
    global $config_file;
    if ($file === false) $file = $config_file;

    $settings = array();
    $doc = new DOMDocument( 1.0 );
    $doc->load($file); 
    $xpath = new DOMXPath($doc); 
    $all=$xpath->query( appSettings/add );
    foreach ($all as $setting) {$settings[$setting->getAttribute( key )]=$setting->getAttribute( value );}

    return $settings;
}

或像这样 :

function read_config($file = false, $config_file = false) {
    if ($file === false && $config_file !== false) $file = $config_file;

    $settings = array();
    $doc = new DOMDocument( 1.0 );
    $doc->load($file); 
    $xpath = new DOMXPath($doc); 
    $all=$xpath->query( appSettings/add );
    foreach ($all as $setting) {$settings[$setting->getAttribute( key )]=$setting->getAttribute( value );}

    return $settings;
}

Answer 2

您可以:

<?php

$greet = function()
{
   return "Hello";
};

$a = $greet();
echo $a;
?>

Read more here: http://php.net/manual/en/functions.anonymous.php

友情链接